The invention relates to a fixing system for fastening cannulas, catheters, etc. to the skin, as well as to a process for the sterile fastening of a cannula to the skin.
Cannulas and catheters are here understood to mean all kinds of "probes" as are used e.g. for introducing into and removing from vessels body fluids and can be in the form of needles, cannulas, catheters, measurement probes (e.g. for measuring certain body perameters, such as the oxygen partial pressure, etc.), as well as infusion means. Cannulas must be secured to the body, e.g. during the dialysis of patients or during longer infusions. Means for fixing cannulas and catheters are known.
EP-B1-76 896 and EP-A1-121 679 discloses a "medical dressing for fixing a probe", having a dressing portion which can be fastened to the skin and to the part of the probe projecting from the skin by means of plasters. This dressing portion is provided with a tubular extension, which serves as a support or reception means for the probe part projecting from the skin.
German utility model 82 04 827.4 describes a holding or retaining device having two clamping plates, which receive the cannula and is then secured by plaster to the skin.
DE-OS 32 12 458 discloses a bandage system for catheters to be externally applied to males and more particularly relates to the geometrical configuration of plaster strips.
German patent DE-PS 29 47 427 relates to a vein catheter bandage which, by means of a plaster with a watertight, air-permeable, pressure sensitive adhesive finished film, which can optionally have a moisture-absorbent layer on the skin-remote side, fixes a cannula with a stop valve to the skin; 95.times.60 mm being given as the preferred dimensions for the plaster.
DE-OS 31 05 187 describes a cannula fixing plaster with a punched out plaster segment which, after the insertion of the cannula, is fixed to the latter and in this way prevents the removal of the cannula, whilst the remaining plaster adheres to the skin.
EP-A1-116 526 relates to another principle for fastening cannulas to the skin, in which a catheter retaining device is fixed by means of a needle passed through the skin of the patient to be treated. In special cases the catheter is even sewn to the skin for fixing it into position.
For example, under the trade name POROFIX cannula plasters, plaster strips are commercially available for fixing such cannulas. They are adhesive plasters with a slit, which is in particular used for fixing Strauss cannulas during infusions.
These known cannula fixing plasters have the advantage that the underlying skin portions can breathe, the film being water vapour and oxygen-permeable, so that there can be no maceration of the skin surface.
However, it is a disadvantage of the known cannula fixing means, that the insertion or puncture point and the underlying skin portions in the puncture or insertion channel are not adequately protected against infections through bacteria which enter from the skin surface. Attempts have been made to at least partly obviate this problem by disinfecting the skin prior to puncturing. However, disinfection only covers the upper skin layers and cannot prevent the penetration of bacteria into the insertion channel from lower lying skin layers or from the outside.
It is important to ensure a good fixing of the cannula, so as to prevent slipping thereof over a long period.
The prior art arrangements only partly solve this problem. It is either necessary to use very complicated means for fixing the cannula, which are stuck to the skin with the adhesive plaster, or simple plasters with incisions or slits are used, which do not lead to a satisfactory, long-term cannula fixing.